Arabidopsis RecQsim gene's Mutation Effect on Growth Rate and Plant Hypersensitivity to UV-Light and Mitomycin-C

RecQ helicases play crucial roles in DNA related processes such as replication and recombination. They are found in a wide range of organisms including bacteria and human. The RecQsim gene is a member of the RecQ family unique to plants. Here, we report on phenotypic analysis of a recQsim mutant of Arabidopsis thaliana in which the RecQsim gene is knocked out by insertional mutagenesis. Under standard growth conditions, recQsim mutant plants grew relatively faster than the wild type and did not exhibit any obvious developmental defects, suggesting that the RecQsim gene is not essential for plant development. The mutant seedlings, however, were found to be more sensitive to ultraviolet light compared with the wild type plants. The wild type and the recQsim mutant seedlings were not different in response to the genotoxic agent methyl methanesulfonate; however, the mutant plants were more sensitive to the genotoxic agent mitomycin C than the wild type. Thus, the Arabidopsis RecQsim gene might be involved in modulation of plant responses to DNA damage. Further detailed functional analysis of RecQsim may reveal novel pathways in signal transduction of genotoxic stress.